Heat-Dissipating Fin, Heat-Dissipating Device, And Method For Enhancing Heat Dissipation Effect Of A Heat-Dissipating Fin

ABSTRACT

In a method for enhancing heat dissipation effect of a heat-dissipating fin, a plurality of heat-conducting particles are affixed directly and contactingly to a part of a surface of the heat-dissipating fin to increase the surface area of the heat-dissipating fin so as to reduce thermal boundary layer effect. A heat-dissipating fin and a heat-dissipating device including a plurality of the heat-dissipating fins are also provided.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of Taiwanese Application No. 098102029, filed on Jan. 20, 2009.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a heat-dissipating fin, a heat-dissipating device, and a method for enhancing the heat dissipation effect of a heat-dissipating fin, more particularly to a heat-dissipating fin having a surface provided with a plurality of heat-conducting particles, a heat-dissipating device including the heat-dissipating fin, and a method for enhancing the heat dissipation effect of the heat-dissipating fin.

2. Description of the Related Art

With the upgrading of the computing efficiency of computers, electronic components, such as central processing units (CPU), video graphics adapters (VGA), North bridge chips, etc., within a computer have to handle more and more data and to process the data at increasing speeds. Consequently, the heat generated by these electronic components during data processing correspondingly increases. Excessively high heat will seriously affect the computational stability and efficiency of the computer.

Therefore, a heat-dissipating device is generally mounted on an electronic component to help speed up dissipation of heat generated by the electronic component. However, in a notebook computer, a conventional heat-dissipating device having a plurality of heat-dissipating fins is no longer capable of achieving effective heat dissipation. The reason for this is that the space available for heat dissipation within the notebook computer is limited, so that the location for mounting the heat-dissipating device and the size of the heat-dissipating device are relatively restricted. As a result, a thermal boundary layer effect is likely to be produced during conduction of heat in the heat-dissipating device. Reference is made to FIG. 1, which shows a conventional heat-dissipating fin 90, and FIG. 2, which illustrates the relationship between temperatures of the conventional heat-dissipating fin 90 measured at positions D0, D1, D2 and the positions D0, D1, D2 when a flow of air moves over the heat-dissipating fin 90 in a direction indicated by the arrow in FIG. 1, wherein the y-axis represents the temperatures of the heat-dissipating fin 90, and the x-axis represents the positions of the heat-dissipating fin 90 over which the air flows and the direction of the airflow. As shown in FIG. 1, the air flows over the heat-dissipating fin 90 from position D0 to position D2, and D0, D1 and D2 are different positions on the heat-dissipating fin 90. Since the heat carried away by the air decreases with an increase in the distance over which the air moves, i.e., the lower the amount of heat that is dissipated, the higher will be the temperature of the heat-dissipating fin 90, the temperature curve gradually ascends from D0 to D1. However, after the air has flowed over position D1 and continues to flow toward position D2, the temperature curve does not rise, which indicates that the amount of heat that can be carried away by the airflow has already reached a saturation point, so that the airflow is unable to carry away any more heat from the heat-dissipating fin 90. This is the so-called thermal boundary layer effect. Thus, the temperature curve from D1 to D2 is approximately horizontal. The thermal boundary layer effect will be more evident in electronic components that generate a large amount of heat during operation. This accounts for why a notebook computer often suffers from poor heat dissipation.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a method for enhancing heat dissipation effect of a heat-dissipating fin.

Accordingly, the method for enhancing heat dissipation effect of a heat-dissipating fin of this invention comprises affixing directly and contactingly a plurality of heat-conducting particles to a part of a surface of the heat-dissipating fin.

Preferably, the heat-conducting particles are affixed to a part of the surface of the heat-dissipating fin using one of a sand-blasting technique and a sintering technique. When the method is for enhancing heat dissipation effect of more than one heat-dissipating fin, heat-conducting particles with a particle diameter not larger than one-tenth of a distance between each adjacent pair of the heat-dissipating fins are selected. In addition, the heat-dissipating fin is formed from a metal material, such as copper or aluminum, and the heat-conducting particles are formed from a metal material with a high coefficient of thermal conductivity, e.g., copper powder, aluminum powder, a mixture of copper and aluminum powders, etc.

Preferably, the distance between each adjacent pair of the heat-dissipating fins is 10⁻³ m, and the heat-conducting particles have a particle diameter of approximately 10⁻⁶ m. Preferably, the particle diameter of the heat-conducting particles ranges between 10⁻⁴ m and 10⁻⁶ m, and more preferably between 10⁻⁵ m and 10⁻⁶ m. From another viewpoint, it can be said that the particle diameter of the heat-conducting particles is in the order of 10⁻⁶ m, i.e., between 1×10⁻⁶ m and 10×10⁻⁶ m.

Furthermore, another object of the present invention is to provide a heat-dissipating fin for enhancing heat dissipation effect. The heat-dissipating fin of the present invention has a surface, at least a part of which is provided with a plurality of heat-conducting particles to increase the surface area of the heat-dissipating fin so as to reduce a thermal boundary layer effect. The heat-conducting particles are affixed to at least a part of the surface of the heat-dissipating fin using one of a sand-blasting technique and a sintering technique.

Preferably, the heat-dissipating fin is formed from a metal material, e.g., copper, aluminum, etc. The heat-conducting particles are formed from a metal material with a high coefficient of thermal conductivity, e.g., copper powder, aluminum powder, a mixture of copper and aluminum powders, etc.

Preferably, the heat-conducting particles have a particle diameter of approximately 10⁻⁶ m. Preferably, the particle diameter of the heat-conducting particles ranges between 10⁻⁴ m and 10⁻⁶ m, and more preferably between 10⁻⁵ m and 10⁻⁶ m. From another viewpoint, it can be said that the particle diameter of the heat-conducting particles is in the order of 10⁻⁶ m, i.e., between 1×10⁻⁶ m and 10×10⁻⁶ m.

In addition, a further object of the present invention is to provide a heat-dissipating device for enhancing heat dissipation effect.

The heat-dissipating device of the present invention comprises a plurality of heat-dissipating fins. At least one of the heat-dissipating fins has a surface, at least a part of which is provided with a plurality of heat-conducting particles to increase the surface area thereof so as to reduce a thermal boundary layer effect. The heat-conducting particles are affixed to at least a part of the surface of the at least one heat-dissipating fin using one of a sand-blasting technique and a sintering technique.

Preferably, the particle diameter of the heat-conducting particles is determined by a distance between the at least one of the heat-dissipating fins and an adjacent one of the heat-dissipating fins, and is not larger than one-tenth of the distance. In addition, the heat-dissipating fin is formed from a metal material, e.g., copper, aluminum, etc. The heat-conducting particles are formed from a metal material with a high coefficient of thermal conductivity, e.g., copper powder, aluminum powder, a mixture of copper and aluminum powders, etc.

Preferably, the distance between the at least one of the heat-dissipating fins and the adjacent one of the heat-dissipating fins is 10⁻³ m, and the heat-conducting particles have a particle diameter of approximately 10⁻⁶ m. Preferably, the particle diameter of the heat-conducting particles is between 10⁻⁴ m and 10⁻⁶ m, and more preferably between 10⁻⁵ m and 10⁻⁶ m. From another viewpoint, it can be said that the particle diameter of the heat-conducting particles is in the order of 10⁻⁶ m, i.e., between 1×10⁻⁶ m and 10×10⁻⁶ m.

The advantageous effect of the present invention resides in that, by forming a plurality of heat-conducting particles on the surface of the heat-dissipating fin to increase the surface area of the heat-dissipating fin, the heat dissipation effect of the heat-dissipating fin can be enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which:

FIG. 1 is a perspective view of a conventional heat-dissipating fin;

FIG. 2 is a plot illustrating the relationship between different positions at the conventional heat-dissipating fin of FIG. 1 and temperatures measured at the different positions;

FIG. 3 is a top view of the preferred embodiment of a heat-dissipating device according to the present invention, the heat-dissipating device being incorporated in a heat-dissipating module and mounted on an electronic component;

FIG. 4 is a perspective view of one of heat-dissipating fins of the heat-dissipating device according to the preferred embodiment; and

FIG. 5 is a plot similar to FIG. 2, but illustrating the thermal boundary layer effect produced in the preferred embodiment according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 3 and 4, the preferred embodiment of a heat-dissipating device 1 according to the present invention can be applied to a heat-dissipating module 2, and can be mounted on an electronic component 3, such as a central processing unit (CPU), a video graphics adapter (VGA), a North bridge chip, etc., to enhance dissipation of heat from the electronic component 3.

In this embodiment, the heat-dissipating module 2 includes a fan 4, a heat pipe 5, and the heat-dissipating device 1. The heat-dissipating device 1 includes a plurality of heat-dissipating fins 10. In this embodiment, the heat-dissipating device 1 includes a plurality of inverted U-shaped heat-dissipating fins 10, as shown in FIG. 4. However, it is apparent from the following description that the heat-dissipating device 1 may be of any type, such as an assembly type, an integral type, etc., and may be of any shape, such as a rectangular shape, a polygonal shape, a circular shape, a radiating shape, etc. The heat pipe 5 of the heat-dissipating module 2 extends through openings of the heat-dissipating fins 10 and is tightly connected to the heat-dissipating fins 10. Thus, heat generated by the electronic component 3 during operation can be conducted to the heat pipe 5 and to the heat-dissipating fins 10 connected to the heat pipe 5, and the fan 4 is operated to create a flow of air so as to carry the heat away from the heat-dissipating fins 10 and hence away from the electronic component 3.

Furthermore, in order to reduce the thermal boundary layer effect so as to permit more heat to be carried away from the heat-dissipating fins 10, the time the air (cool air) flows over the heat-dissipating fins 10 has to be prolonged, i.e., prolonging the exchange of heat between the heat-dissipating fins 10 and the air (cool air) around them. Therefore, referring to FIG. 4, in the heat-dissipating device 1 of this embodiment, a plurality of heat-conducting particles 11 are affixed to the surface of each of the heat-dissipating fins 10. The heat-conducting particles 11 have surfaces that are partially in direct contact with the surfaces of the heat-dissipating fins 10 so as to increase the surface area of each of the heat-dissipating fins 10, thereby prolonging the time needed for the air to flow over the heat-dissipating fins 10. Reference is made to FIG. 5, which illustrates the thermal boundary layer effect produced in the heat-dissipating fins 10 of the preferred embodiment. Compared to FIG. 2, the point at which the amount of heat carried away by the airflow reaches a saturation point is advanced from position D1 in FIG. 2 to position D1′ in FIG. 5. That is to say, the amount of heat that can be carried away by the airflow in this embodiment increases significantly in contrast to the conventional heat-dissipating fin 90 which has no heat-conducting particles 11 affixed thereto, and the thermal boundary layer effect in the heat-dissipating fins 10 is significantly reduced.

In practice, the heat-dissipating fins 10 of this embodiment are fabricated by first preparing fin bodies. In this embodiment, the fin bodies are metal plates of, e.g., copper or aluminum, and have a surface area of 400 mm². Subsequently, according to the distance between each adjacent pair of the fin bodies, heat-conducting particles 11 having a suitable particle size and any shape are selected. The reason for selecting suitably sized heat-conducting particles 11 is that, since the heat-dissipating device 1 generally includes a plurality of heat-dissipating fins 10 for heat dissipation, if the particle size of the heat-conducting particles 11 is too large, the heat-conducting particles 11 may be jammed between a clearance between each adjacent pair of the heat-dissipating fins 10, which will adversely affect heat dissipation instead of enhancing it. Thus, the particle diameter of the heat-conducting particles 11 should not be larger than one-tenth of the distance between each adjacent pair of the heat-dissipating fins 10. In this embodiment, the distance between each adjacent pair of the heat-dissipating fins 10 is 10⁻³ m. Therefore, the heat-conducting particles 11 may be copper powder particles or aluminum powder particles, and the particle diameter of the heat-conducting particles 11 may be approximately 10⁻⁶ m. Preferably, the particle diameter of the heat-conducting particles 11 ranges between 10⁻⁴ m and 10⁻⁶ m, and more preferably between 10⁻⁵ m and 10⁻⁶ m. From another viewpoint, it can be said that the particle diameter of the heat-conducting particles 11 is in the order of 10⁻⁶ m, i.e., between 1×10⁻⁶ m and 10×10⁶ m.

After the heat-conducting particles 11 are selected, the heat-conducting particles 11 are affixed directly and contactingly to the entire surface of each of the heat-dissipating fins 10 using a sand-blasting technique to thereby form the heat-dissipating fins 10 of this embodiment. The surface area of each of the heat-dissipating fins 10 thus formed can be increased by 100 mm². If the heat-dissipating device 1 has fifty-five heat-dissipating fins 10, the overall surface area of the heat-dissipating fins 10 can be increased by 5500 mm², and the heat dissipation effect will be far superior to that of heat-dissipating fins without the heat-conducting particles 11. It is noted that the heat-conducting particles 11 affixed to the heat-dissipating fins 10 are formed from a material with a high coefficient of thermal conductivity, such as a metal material or a mixture of various metal materials, like copper powder, aluminum powder, a mixture of copper powder and aluminum powder. The heat-conducting particles 11 may not necessarily be formed from the same material as the heat-dissipating fins 10. For example, aluminum powder may be affixed to copper heat-dissipating fins 10. Moreover, the method of affixing the heat-conducting particles 11 is not limited to sand-blasting technique, and may include sintering technique. That is, the heat-conducting particles 11 may be attached to the heat-dissipating fins 10 by sintering, spraying, gluing, etc.

Referring to FIG. 4, each of the heat-dissipating fins 10 of this embodiment has a first surface 101 and a second surface 102, and the heat-conducting particles 11 may be affixed to a part or parts of the first surface 101 or the second surface 102 of the heat-dissipating fins 10 or to one of the first and second surfaces 101, 102. In addition, in this embodiment, a plurality of the heat-dissipating fins 10 are first assembled to the heat-dissipating device 1, and the heat-conducting particles 11 are sprayed onto the heat-dissipating device 1 in a single operation using a sand-blasting technique. On the other hand, the heat-conducting particles 11 may be sprayed onto each of the heat-dissipating fins 10 before assembling the heat-dissipating fins 10 to the heat-dissipating device 1. Certainly, the type of the heat-dissipating device 1 is not limited to what is disclosed herein. If the heat-dissipating device 1 is not of an assembled type, the heat-conducting particles 11 can be sprayed directly and contactingly onto the heat-dissipating device 1 without being limited to this embodiment.

In sum, in the heat-dissipating device 1 of this invention, the surface area of the heat-dissipating fins 10 can be increased by affixing directly and contactingly the heat-conducting particles 11 to the heat-dissipating fins 10 using a sand-blasting technique or a sintering technique to prolong the time needed for airflow to move over the heat-dissipating fins 10 and increase the amount of heat that can be carried away by the airflow to thereby achieve a better heat dissipation effect.

While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements. 

1. A method for enhancing heat dissipation effect of a heat-dissipating fin, comprising affixing directly and contactingly a plurality of heat-conducting particles to apart of a surface of the heat-dissipating fin.
 2. The method for enhancing heat dissipation effect of a heat-dissipating fin of claim 1, wherein the heat-dissipating fin and the heat-conducting particles are formed from a metal material.
 3. The method for enhancing heat dissipation effect of a heat-dissipating fin of claim 2, wherein the heat-conducting particles are one of copper powder particles and aluminum powder particles.
 4. The method for enhancing heat dissipation effect of a heat-dissipating fin of claim 3, wherein the heat-conducting particles are affixed to the surface of the heat-dissipating fin using one of a sand-blasting technique and a sintering technique.
 5. The method for enhancing heat dissipation effect of a heat-dissipating fin of claim 4, wherein, when said method is for enhancing heat dissipation of more than one heat-dissipating fin, heat-conducting particles with a particle diameter not larger than one-tenth of a distance between each adjacent pair of the heat-dissipating fins are selected for affixing to the surfaces of the heat-dissipating fins.
 6. The method for enhancing heat dissipation effect of a heat-dissipating fin of claim 5, wherein the heat-conducting particles have a particle diameter ranging between 10⁻⁴ m and 10⁻⁶ m.
 7. The method for enhancing heat dissipation effect of a heat-dissipating fin of claim 6, wherein the heat-conducting particles have a particle diameter ranging between 10⁻⁵ m and 10⁻⁶ m.
 8. The method for enhancing heat dissipation effect of a heat-dissipating fin of claim 1, wherein the heat-conducting particles are affixed to the entire surface of the heat-dissipating fin.
 9. A heat-dissipating fin, comprising a fin body and a plurality of heat-conducting particles affixed to a part of a surface of said fin body.
 10. The heat-dissipating fin of claim 9, wherein said fin body and said heat-conducting particles are formed from metal, each of said heat-conducting particles having a surface partially in direct contact with said surface of said fin body.
 11. The heat-dissipating fin of claim 10, wherein said heat-conducting particles are one of copper powder particles and aluminum powder particles.
 12. The heat-dissipating fin of claim 11, wherein said heat-conducting particles have a particle diameter ranging between 10⁻⁴ m and 10⁻⁶ m.
 13. The heat-dissipating fin of claim 12, wherein said heat-conducting particles have a particle diameter ranging between 10⁻⁵ m and 10⁻⁶ m.
 14. The heat-dissipating fin of claim 9, wherein said heat-conducting particles are affixed to the entire surface of said fin body.
 15. A heat-dissipating device, comprising a plurality of heat-dissipating fins, wherein at least one of said heat-dissipating fins has a surface, at least a part of which is provided with a plurality of heat-conducting particles.
 16. The heat-dissipating device of claim 15, wherein said heat-dissipating fins and said heat-conducting particles are formed from metal, each of said heat-conducting particles on said at least one heat-dissipating fin having a surface that is partially in direct contact with said surface of said at least one heat-dissipating fin.
 17. The heat-dissipating device of claim 16, wherein said heat-conducting particles are one of copper powder particles and aluminum powder particles.
 18. The heat-dissipating device of claim 17, wherein said heat-conducting particles have a particle diameter not larger than one-tenth of a distance between said at least one of said heat-dissipating fins and an adjacent one of said heat-dissipating fins.
 19. The heat-dissipating device of claim 18, wherein said heat-conducting particles have a particle diameter ranging between 10⁻⁴ m and 10⁻⁶ m.
 20. The heat-dissipating device of claim 19, wherein said heat-conducting particles have a particle diameter ranging between 10⁻⁵ m and 10⁻⁶ m.
 21. The heat-dissipating device of claim 15, wherein said heat-conducting particles are affixed to the entire surface of said at least one of said heat-dissipating fins. 